Colo-colonic intussusception secondary to a giant colonic submucosal lipoma in a cat.

Case summary: A 16-year-old male castrated domestic shorthair cat was referred for investigation of a 2-week history of lethargy, hyporexia, and intermittent diarrhoea and constipation. CT revealed a colo-colonic intussusception associated with a fat attenuating non-contrast enhancing mass measuring 4.5 × 2.6 cm, arising from the ventral aspect of the intussuscipiens, causing partial obstruction. Surgical intervention involved manual reduction of the intussusception, colectomy with 3 cm margins and end-to-end anastomosis. Histopathological examination identified the mass as a lipoma, composed of well-differentiated adipocytes originating within and expanding into the submucosa of the intestine, with an ulcerated and necrotic luminal surface. The cat was discharged 3 days postoperatively and had fully recovered at the 10-day follow-up. At 9 months postoperatively, the patient continued to do well with no recurrence of clinical signs. Relevance and novel information: To the best of our knowledge, this is the first reported case of a colonic lipoma and the first reported case of a colonic submucosal lipoma leading to intussusception in a cat. This case highlights the importance of considering colonic lipomas as a differential diagnosis in feline patients presenting with constipation, diarrhoea or an acute abdomen.